Many recreational vehicles, such as motor homes and travel trailers, utilize both 110-volt ac and 12-volt dc. For example, the 110-volt ac may be used for air conditioning units and for operating various applicances while the interior lights of the recreational vehicle may be operated on 12-volt dc. When electrical hook-ups are used, it is necessary to convert the 110-volt ac from the electrical hook-up to 12-volt dc to operate the lights and the other direct current electrical devices within the recreational vehicle while also supplying the 110-volt ac to those circuits of the recreational vehicle which require it. These functions are performed by a converter.
Converters of this type typically include a step-down transformer which reduces the 110-volt ac to a lower voltage level, such as 12 volts and a rectifier for converting the ac to dc. Although these are relatively simple functions, their adaptation to recreational vehicles introduces a number of significant problems. For example, space is at a premium in recreational vehicles and so the dimensions of equipment, such as converters, must be held to a minimum. Similarly, it is desired to minimize the weight of accessory equipment carried by the recreational vehicle. Unfortunately, prior art converters are larger and heavier than desired.
Transformer hum is also very undesirable in recreational vehicles because of the proximity of the occupants to the transformer and because the sleeping accommodations of the recreational vehicle are typically not far from the transformer. It is also important that the circuit elements of the converter be readily accessible from the interior of the recreational vehicle so that the converter can be easily repaired and maintained. All of these objectives must be accomplished without increasing the cost of the converter beyond what is considered acceptable in the recreational vehicle market.